Can I make my glasses stronger?
September 29, 2020 4:07 PM   Subscribe

I wish to superpower my prescription glasses.

Hi there, I recently got an updated eyeglass prescription, and was wondering if I could bump down the sphere numbers to make my vision even sharper. Right now my right eye is sphere -2.25, no cylinder or axis, and my left eye is sphere -2.0, cylinder -0.75 and axis 40. Could I request, for example, sphere -2.75 and -2.5, or would that make things wonky? My glasses are single vision, so it doesn't seem like the 'add' value is what I'm looking for.
posted by Evilspork to Health & Fitness (14 answers total) 1 user marked this as a favorite
Have you talked about the possibility of having an astigmatism with your optometrist?
posted by Kitchen Witch at 4:16 PM on September 29, 2020 [3 favorites]

Please discuss this with your eye doctor!
posted by aquamvidam at 4:26 PM on September 29, 2020 [6 favorites]

Best answer: This is a straight out no. You don't need to discuss this with an optometrist, let alone an ophthalmologist. If a stronger prescription was more suitable for you, it would have been prescribed for you in the test.
posted by ambrosen at 4:37 PM on September 29, 2020 [13 favorites]

Best answer: As a lifelong eyeglass-wearer, I once had a prescription bumped up past the point that was strictly necessary (I was in my early teens, so I can't remember if the optometrist messed up, or if I just overshot the response on the test because I was a kid), but I can tell you this: it's a recipe for rockin' headaches.
posted by mandolin conspiracy at 4:44 PM on September 29, 2020 [14 favorites]

Best answer: My understanding is that it doesn't really work like that. Your eyeballs are a certain shape, and the lens is curved in a particular way so that the light hits the back of your eye 'perfectly'. Adjusting the prescription as proposed will just move it off perfect in a different direction. The main caveat to this is that it's unlikely that your assessment of 'better' and 'worse' when getting your prescription is perfect, and the perfect prescription for you could be in between two standard jumps.

If you think your vision could/should be sharper, go back and get a new prescription.
posted by plonkee at 4:57 PM on September 29, 2020 [6 favorites]

Best answer: I have found that it is important for the glasses maker to be very precise with the lens making. (even more important with progressive lenses and strong prescriptions). The glasses I have right now have the right lens perfectly made for looking straight forward, but the best focus with the left lens happens when I look straight forward, but turn my head about 5 degrees to the left. The end result is vision that is technically corrected to near 20-20, but not as crisp in focus as I know is possible.
posted by coppertop at 6:18 PM on September 29, 2020 [2 favorites]

What do you want to 'super power'? If it is close reading then reading glasses will help with that. You can just test it at a store with over the counter ones to get the bifocal effect.
posted by aetg at 6:56 PM on September 29, 2020

Response by poster: "What do you want to 'super power'?"

My vision is fine with glasses, I was just wondering if the general power/clarity could be boosted by fiddling with the numbers. Thank you all for your replies!
posted by Evilspork at 7:32 PM on September 29, 2020

Best answer: My optometrist did make me a more powerful pair of glasses at my request, for a specific purpose: for work I need to be able to make fine, crisp focus adjustments on a screen across a large room, and my ordinary walkin-around glasses don’t focus crisply at that distance. (Bad eyes, astigmatism, etc.)

However, I only put them on to do those focus adjustments. Wearing them otherwise is difficult—looking into the middle distance is a strain, and trying to look closer is painful. So unfortunately I don’t get to have superhero vision. :(
posted by theatro at 7:38 PM on September 29, 2020 [3 favorites]

Best answer: How did your eye doctor do your exam? Did they ask you which was better, 1 or 2, 2 or 3, etc?

Because if a stronger prescription was better, you would have told them so.
posted by Huffy Puffy at 6:27 AM on September 30, 2020 [1 favorite]

Yeah, the closest I'll ever have to super-powers is that with my -3.75 vision, I can take my glasses off and see small things more clearly. The problem is that the focal length is so close that I can't use both eyes simultaneously. So right not I use contact lenses + reading glasses like a normal oaf.
posted by Dmenet at 7:26 AM on September 30, 2020 [1 favorite]

Best answer: If you think of your eye as a camera, then understand that if you need glasses, it's because the camera is out of focus. The glasses put the camera back into focus, but they can't increase the resolution of the sensor. Imagine that you are focusing a camera or a pair of binoculars, and you twist the focus knob until the object you are looking at is perfectly in focus. Will twisting it further in the same direction help? No, it will just take the object back out of focus. You're looking for the option to buy a higher-resolution camera or one with a zoom lens, but that doesn't exist for eyes, sorry.
posted by agentofselection at 11:29 AM on September 30, 2020 [1 favorite]

Response by poster: How did your eye doctor do your exam? Did they ask you which was better, 1 or 2, 2 or 3, etc?

Yes, they did the standard(?) 1/2, 2/3 test.
posted by Evilspork at 1:37 PM on September 30, 2020

Let's take the situation where your eyes are completely fixed-focus. This is the situation everyone eventually gets into, usually some time between the ages of say 40 and 55. It's called presbyopia - read more here (but note that for some inscrutable reason they always emphasize "worsening ability to focus clearly on close objects" when actually it is the loss of ability to change focus at all. For example I can focus perfectly on items at about 4 inches distance--that's pretty close. But I can't focus any closer OR any further, as I once could).

With completely fixed-focus eyes, what eyeglasses do is they set your point of focus. So you put on one pair of glasses and your focus is at 2 inches. Anything closer or further away is blurry.

Another pair with a different strength sets your focus at 4 inches. Another pair sets it a 8 inches, another at 16, another at 32, and so on.

(Note that I've doubled the distance at each step--that's about how it works, more or less. You're going to have some range in & out from the focus point where it is still "good enough".)

Finally you get out to "infinity" focus, which (puts on own "infinity focus" glasses to check) works OK from say 15 feet out to infinity.

Now if you keep going from there, what you get is focal points that are out beyond infinity. As you might imagine, that is pretty much useless. If the focal point is just a bit beyond infinity you'll still be able to see distant things OK--maybe it will be 30 feet & greater, say, rather than 15 feet & greater--but if the focal point starts getting too far beyond infinity then you won't be able to focus on anything at all, no matter how far away.

Beyond that, everything just becomes blurrier and blurrier, no matter what.

So short answer is, you can get a focal point that is closer and closer and closer by varying the prescription. And you can make the focal point further and further away, to a point.

But that's pretty much it. That's the limit of the "magic" one can perform by getting stronger or weaker glasses prescriptions.

FYI even for people whose eyes can adjust their focus point, the adjustment for further distance is always at the expense of near-distance focus. So for example, often as patients enter that age range where their focal range is limited but not yet completely gone, eye doctors will fudge their prescription a notch or two inwards, meaning that their vision at far distances is just a bit fuzzy but as a tradeoff, they can see close things--say to read or use a computer--a little better.

In day-to-day life, for the vast majority of people, close vision is used far, far more often than distant vision. So this is a reasonable trade-off for most.

(Arriving at the age of 55 I finally understood why short-sightedness is not a genetic defect selected against by evolution. Losing your distance vision is bad, but losing all your close-up vision is disastrous--life-threatening if you have no way to fix it.)

So one bit of magic you CAN do if you are in the partially or completely presbyopic population, is ask your eye dr to give you a prescription for an extra pair of glasses that are calibrated to focus RIGHT at infinity instead of fudging it a bit inwards.

You'll probably want to wear those only for outdoor activities, star gazing, etc but what you'll find is, for example, stars at night go from being small slightly fuzzy disks to actual pinpoints. And you can see distant details very, very clearly--important if you are, say, a hunter.

I have a pair of "infinity" glasses and I actually really love them when doing outdoor activities or stargazing. They are noticeably better at distance than (for example) my pair of progressive lenses, which theoretically allow focus anywhere from a few inches to infinity but in reality fudge both ends of that a bit. BUt... around the house the infinity focus really does drive you a bit crazy and give you headaches.

The "infinity focus" pair of glasses is a trick many amateur astronomers and other outdoor types use when they reach their 40s & beyond.

Another trick some do (musicians, for example) is one eye set at fairly close focus and one at distant or middle-distance. You can do this via glasses, contacts, or laser vision correction. That way you can see the music stand clearly with one eye while still seeing the conductor (or orchestra/band/choir, in the case you are the conductor) with the other.
posted by flug at 1:24 PM on October 1, 2020 [10 favorites]

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